Redis

Why there is no ordered hashmap in Redis?

由 我只是一个虾纸丫 提交于 2021-02-07 09:58:26
问题 Redis Data types includes sorted set and other necessary data-structures for key-value storage. But I wonder why it doesn't have any sorted map like Java's TreeMap or C++'s std::map . I think the underlying data-structure would be mostly similar of sorted set as both are supposed to be balanced binary search tree. There must be some use-cases where we have to store key-value pair in specific order according to key. But current sorted set only serves the purpose of storing key according to

Why there is no ordered hashmap in Redis?

由 南笙酒味 提交于 2021-02-07 09:58:22
问题 Redis Data types includes sorted set and other necessary data-structures for key-value storage. But I wonder why it doesn't have any sorted map like Java's TreeMap or C++'s std::map . I think the underlying data-structure would be mostly similar of sorted set as both are supposed to be balanced binary search tree. There must be some use-cases where we have to store key-value pair in specific order according to key. But current sorted set only serves the purpose of storing key according to

Why there is no ordered hashmap in Redis?

由 假如想象 提交于 2021-02-07 09:57:00
问题 Redis Data types includes sorted set and other necessary data-structures for key-value storage. But I wonder why it doesn't have any sorted map like Java's TreeMap or C++'s std::map . I think the underlying data-structure would be mostly similar of sorted set as both are supposed to be balanced binary search tree. There must be some use-cases where we have to store key-value pair in specific order according to key. But current sorted set only serves the purpose of storing key according to

Java面试复习体系总结（2021版）

由 ぃ、小莉子 提交于 2021-02-07 09:29:57
Java面试复习体系总结（2021版） 一、Java基础 内容 Java基础（一）：Java集合框架（超详细解析，看完面试不再怕） Java基础（二）：迭代器（Iterator）（含使用方法详解） Java基础 （三）：LinkedList（含使用方法详解） Java基础（四）：ArrayList（含使用方法详解） Java基础（五）：HashSet（使用方法详解） Java基础（六）：HashMap（使用方法详解） Java基础（七）：栈 Stack（使用方法详解） Java基础：详解Arrays.asList() （代码分析） Java基础知识（超详细解析，排班清晰！）：super关键字 Java基础知识（超详细解析，排班清晰！）：多态 Java基础知识（超详细解析，排版清晰！）：Java继承 Java基础知识（超详细解析，排版清晰！）：this关键字 Java基础知识（超详细解析，排版清晰！）：Java抽象 二、Java面试突击 内容 Java面试突击系列（一）：消息队列的面试连环炮 Java面试突击系列（二）：分布式搜索引擎的面试连环炮 Java面试突击系列（三）：分布式缓存 Java面试突击系列（四）：Redis面试常见问题 Java面试突击系列（五）：Redis集群模式 Java面试突击系列（六）：分布式系统 Java面试突击系列（八）：分布式Session方案

How to cache a complex object such as Map<String, List<Car>> in a Spring Boot app

由 北城以北 提交于 2021-02-07 08:27:01
问题 My spring boot app has many complex objects of type Map<String, List<Car>> that I like to cache somewhere. I don't want to use a static variable within the program for that, as if the application will run behind a load balancer, each instance might get different results from its own memory cache, and changes in one application will not take effect in the other. So I was looking at Redis & its Jedis client, but it seems like we can only cache items in a map with the type of <String, String>

How to cache a complex object such as Map<String, List<Car>> in a Spring Boot app

由 你离开我真会死。 提交于 2021-02-07 08:26:05
问题 My spring boot app has many complex objects of type Map<String, List<Car>> that I like to cache somewhere. I don't want to use a static variable within the program for that, as if the application will run behind a load balancer, each instance might get different results from its own memory cache, and changes in one application will not take effect in the other. So I was looking at Redis & its Jedis client, but it seems like we can only cache items in a map with the type of <String, String>

How to cache a complex object such as Map<String, List<Car>> in a Spring Boot app

由 折月煮酒 提交于 2021-02-07 08:25:16
问题 My spring boot app has many complex objects of type Map<String, List<Car>> that I like to cache somewhere. I don't want to use a static variable within the program for that, as if the application will run behind a load balancer, each instance might get different results from its own memory cache, and changes in one application will not take effect in the other. So I was looking at Redis & its Jedis client, but it seems like we can only cache items in a map with the type of <String, String>

Redis command to get all available keys on Redis Cluster?

由 ぐ巨炮叔叔 提交于 2021-02-07 04:56:23
问题 I am using this redisManager.redisClient.keys('*example*', function (err, keys) { }) But it only gives keys from only one of the redis cluster. How can I get keys from all cluster? 回答1: You can't get keys for all nodes using a single command. You have to get keys for all nodes and merge them. Reference - https://github.com/antirez/redis/issues/1962 You can do something like. var redis = require('redis'); redisConfig = new Array( {"port": 1234, "host": "192.168.1.2"}, {"port": 5678, "host":

Redis性能调优，影响Redis性能的因素

由 和自甴很熟 提交于 2021-02-07 02:46:29
序言 上一篇文章《Redis为什么这么快》介绍了Redis性能评估工具，以及Redis高性能的原因。详细请见： 这篇我们将从业务的视角，讲解下影响Redis性能的因素以及如何提升Redis使用的性能。 从用户到Redis请求过程分析 以最常用场景缓存为例，流量从用户到Redis Server的过程如下所示： image 用户访问后端服务器，调用对应的Controller Controller命中缓存记录，通过Jedis客户端调用Reids从缓存获取记录。 如果使用的Jedis连接池获取Jedis对象，从Jedis连接池获取一个Jedis连接实例。 Jedis使用Redis序列化协议(RESP)将命令编码，放到Redis Server输入缓冲区中。 Redis Server从输入缓冲区获取命令并执行。 执行结束后将执行结果放入到输出缓冲区。 Jedis客户端从输出缓冲区获取执行结果并返回给Controller。 Controller执行完业务逻辑相应用户的请求。 从上面时序图可以看出，用户请求通过Redis client经由网路到达Redis Server。 因此在考虑使用Redis性能的时候要从客户端和服务端两个角度考虑。 对于业务方来说， 合理使用Redis特性比Redis服务器的优化可操作性更强，也更容易获得好的效果。 下面将从业务优化和服务器优化两个方面介绍Redis的优化。

Persistent in-memory Python object for nginx/uwsgi server

由 微笑、不失礼 提交于 2021-02-07 02:44:29
问题 I doubt this is even possible, but here is the problem and proposed solution (the feasibility of the proposed solution is the object of this question): I have some "global data" that needs to be available for all requests. I'm persisting this data to Riak and using Redis as a caching layer for access speed (for now...). The data is split into about 30 logical chunks, each about 8 KB. Each request is required to read 4 of these 8KB chunks, resulting in 32KB of data read in from Redis or Riak.
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